APEX Report

April 28-29, 2009May 4, 2009

Fulvia Pilat

Time Meeting, May 12 2009

APEX Schedule April 28-29 2009

5am9pm7pm 11:30pm

Injection

08-29, 08-10Polarimeter studyHuang, Zelenski+team

2am

RampsBBQ

09-26DA measurementwith AC dipoleBaiPilat

7am

InjectionBBQ106turn BPMAC dipole

07-19, 07-20Noise fromMain PSSchultheissMinty

09-05D0-DX studyMacKaySatogata

08-08Long Rangebeam-beamFischer+team

StoreBBQ

Injection

APEX Schedule May 4th 2009

9am noon

Injection

3pm

RampsBBQ

4pm

07-19, 07-20Noise fromMain PSSchultheissWilinsky

09-05D0-DX studyMacKaySatogata

RHIC/AGS Polarimeter Study

• Fixed target polarization for two intensities (1.4 and 1.6*1011) with 12 bunches in both rings with two polarimeters. AGS measurements were done with similar intensity.

• Polarization profile measurements were done with both rings and both planes with 56 bunches. AGS horizontal and vertical profiles were taken the same time.

• Sweep and fixed target measurements were done with 56 bunches for comparison.

• Note: Keith tuned emittance down for AGS before the study, we did not see much change on AGS IPM or CNI target scan, but the polarization profiles measured in AGS is flatter than before.

Huang, Zelenski+team

Polarization Profiles of RHIC and AGS

Ring Horizontal P0 sigma Vertical P0 sigma

AGS 60.453+-3.341 3.981+-1.909 60.979+-2.374 3.994+-1.491

Blue 55.915+-2.623 3.462+-1.258 60.089+-1.860 4.804+-2.294

Blue 64.523+-1.631 3.386+-0.427

Yellow 58.923+-1.162 3.732+-0.500 57.904+-1.661 3.482+-0.447

•The profiles are consistent between AGS and RHIC with the statistics.•The actually is P / I. These numbers from last year at 100GeV are averaged 2.5, this year is about 3(average of many fills). Given the large error bars, I can’t say there is profiles developed in RHIC ramp.

PS beam noise - summary

Four ramps were executed with different configurations of the electrostatic shield and a capacitor across the grounding resistors.

Ramp Number

Blue Dipole Ramp Electrostatic Shield

Yellow Dipole Ramp Electrostatic Shield

Capacitor in Yellow Dipole Ramp OCC

1 Floating Switched In and Out Not Installed 2 Floating Grounded Installed for

Entire Ramp 3 Grounded Grounded Switched In and Out 4 Floating Floating Not Installed

Schultheiss, Minty

Ramp 1 Results

Conclusions Floating the Electrostatic Shields in the

Dipole Ramp PM reduced the noise during the ramp. Yellow showed more reduction than Blue.

The Capacitor had a less dramatic reduction in the noise.

The present configuration is with the shields floating and no capacitor.

Plan for the experiment Use pattern BBLR_34x34 (28x28 + 6 non-colliding bunches),

2e11/bunch, accelerate and collide, will not ramp up the RF voltage

CNI emittance measurement => emittances measured around 35 (Blue) and 22 (Yellow) mm.mrad : BBQ was left one during the ramp

5A, position scan in Blue and Yellow, orbit and BTF measurements

Retract, CNI emittance measurement => around 50 (Blue) and 22 (Yellow) mm.mrad

50A, position scan in Blue and Yellow, orbit and BTF measurements

Retract, CNI emittance measurement

Time permitting, change chromaticity, repeat one scan

FischerRobert-DemolaizeCalaga

Conclusion Plan executed: distance scans with both 5A and 50A scans in

both beams, including head-on beam-beam.

Suffered from larger than usual emittance (about 30 mm.mrad); BBQ should be off next time.

Additional beam time to study in details the behavior of non-colliding bunches + chromaticity changes ?

MacKay, Satogata

APEX Schedule May 12-13 2009

5am10pm7pm 1am

InjectionHigh intensity

3am

09-17Space charge andBeam-beam

Fedotov + team

7am

09-06Off-momentumbeta-beat

CalagaGlenn

08-08Long Rangebeam-beam

FischerDemolaize+team

StoreBBQ

InjectionInjectionInjectionHigh intensityGamma-TNo snakes

09-21Bunch lengthlimit

Ptitsyn+ team

09-07Impedance

Calaga